The Mininch Pen Tool Mini is as precision hand tool that fits in your pocket and feels/ looks like a normal pen. Machined out of a single piece of metal, the body of the pen tool is strong and sturdy feeling, the magnets in the bits give you a feel of the tight connections and the small parts inside don't shake or rattle. The functionality is like that of the old mechanical pencils I had in elementary school: you push a bit in the back and one comes out of the front. But when you're pushing from the front, there is a lock mechanism that keeps the bits from coming out the back, allowing you to use the appropriate pressure. While heading out for a weekend, I noted that my sunglasses took one bit size, my pocket knife another, and three for small adjustments on my bike. I packed those five bits into the pen, put the pen in my pocket, and I can rest easy knowing that I have those areas of maintenance covered if I need to address anything.